نتایج جستجو برای: damping ratio

تعداد نتایج: 522587  

Journal: :Asymptotic Analysis 2016
Muhammad I. Mustafa

In this paper we consider a plate equation with internal feedback and viscoelastic damping localized on a part of the boundary. Without imposing restrictive assumptions on the time-dependent frictional damping, we establish an explicit and general decay rate result that allows a wider class of relaxation functions and generalizes previous results existing in the literature.

2015
Delin Sun Ridong Liao

At the initial phase of the mechanical product development, it is very important to effectively obtain the modal damping ratio of the bolted joint structure for accurately predicting dynamic response. The energy dissipation has been estimated using a finite element model incorporating the effect of pretension force of the bolted joint. First, the modal damping ratios of the first four modes are...

A. Ghorbanpour-Arani, M. Shokravi

This paper is concerned with the surface and small scale effects on transverse vibration of a viscoelastic single-layered graphene sheet (SLGS) subjected to an in-plane magnetic field. The SLGS is surrounded by an elastic medium which is simulated as Visco-Pasternak foundation. In order to investigate the small scale effects, the nonlocal elasticity theory is employed due to its simplicity and ...

2014
Farid Khan Boris Stoeber Farrokh Sassani

The simulation results for electromagnetic energy harvesters (EMEHs) under broad band stationary Gaussian random excitations indicate the importance of both a high transformation factor and a high mechanical quality factor to achieve favourable mean power, mean square load voltage, and output spectral density. The optimum load is different for random vibrations and for sinusoidal vibration. Red...

Journal: :NHM 2016
Maria Colombo Gianluca Crippa Stefano Spirito

The aim of this short note is twofold. First, we give a sketch of the proof of a recent result proved by the authors in the paper [7] concerning existence and uniqueness of renormalized solutions of continuity equations with unbounded damping coe cient. Second, we show how the ideas in [7] can be used to provide an alternative proof of the result in [6, 9, 12], where the usual requirement of bo...

2012
B. Singh K. K. Agrawal B. K. Nanda

In built-up structures, one of the effective ways of dissipating unwanted vibration is to exploit the occurrence of slip at the interfaces of structural laminates. The present work focuses on the dynamic analysis of welded structures. A mathematical formulation has been developed for the mechanism of slip damping in layered and welded mild steel beams with unequal thickness subjected to both pe...

2007
H. Yamagishi M. Fukuhara

Cyclic-tension fatigue of aluminum alloy, Al-4Cu-1Mg, was determined by an analysis of diffracted SH and SV waves, passing through the surface and reflecting the bottom of the specimen, respectively. The internal friction of SV waves begins to increase from fatigue damage ratio(=N/Nf) of 0.5. This suggests increase of movable dislocation. From the analysis of SH waves, the logarithmic damping r...

1967
By N. C. LAMBOURNE

The influence of damping is examined by comparing the flutter critical speeds and frequencies obtained using the complete equations of motion and those obtained when all the damping terms are omitted. The calculations are made for binary flexure-torsion flutter of a wing in incompressible flow and the comparisons extend over ranges of values of the principal parameters. When the ratio of air de...

1996
John G. Maneatis

Delay-locked loop (DLL) and phase-locked loop (PLL) designs based upon self-biased techniques are presented. The DLL and PLL designs achieve process technology independence, fixed damping factor, fixed bandwidth to operating frequency ratio, broad frequency range, input phase offset cancellation, and, most importantly, low input tracking jitter. Both the damping factor and the bandwidth to oper...

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